In the Australian climate, where we deal with everything from scorching summer heatwaves to biting winter mornings, understanding how heat moves through your home is the first step to creating a more energy-efficient space.
What is Thermal Bridging?
Thermal bridging is a process where heat finds a “path of least resistance” to travel through a building material that conducts heat better than the surrounding insulation. Think of it as a “heat highway” that allows warmth to bypass your insulation and escape outside during winter, or sneak inside during summer.
To picture this, imagine you are wearing a thick, high-quality woollen jumper on a windy day, but the jumper has a large metal zip running down the front. While the wool keeps your body heat in, the metal zip gets ice-cold and allows the heat to skip right past the wool. In your home, the “wool” is your insulation, and the “zip” is the timber or steel frame of your house.
In a standard Australian home, insulation is usually placed between the studs of the wall. However, the studs themselves (the wood or metal beams) aren’t insulated. Because materials like steel and timber conduct heat much faster than glasswool or foam, the heat travels through those beams, “bridging” the gap between the inside and outside of your home.
Why is Thermal Bridging a Problem for Your Home?
Thermal bridging is a problem because it significantly reduces the effectiveness of your insulation, leading to higher energy bills, uncomfortable indoor temperatures, and potential issues with condensation and mould. Even if you have the highest-rated insulation “batts” in your walls, thermal bridges can reduce their overall performance by up to 25% or more.
There are three main reasons why you want to avoid this in your Australian home:
Wasted Money: When heat escapes through the wall studs in winter, your heater has to work twice as hard to maintain a comfortable temperature. This shows up directly on your quarterly power bill.
Ghosting and Staining: Have you ever seen dark streaks or “ghost marks” on a ceiling or wall that perfectly outline the timber frames behind the plasterboard? This is caused by thermal bridging. The cold spots on the wall attract dust and moisture, eventually leaving marks that are hard to clean.
Condensation and Mould: When warm, moist air inside your home hits a cold spot on a wall caused by a thermal bridge, it turns into water droplets (condensation). Over time, this moisture can lead to mould growth behind your walls, which can damage your structure and affect your family’s health.
Where Does Thermal Bridging Usually Happen?
Thermal bridging occurs most frequently at points where the building envelope is interrupted, such as wall studs, floor joists, roof rafters, and around window or door frames. Basically, anywhere a solid material connects the interior lining of your house to the exterior cladding, you have a potential thermal bridge.
Steel Frames: This is a major one for modern Aussie homes. Steel is an incredible conductor of heat—much more so than timber. Without a “thermal break,” a steel-framed house can feel like an oven in the summer and a fridge in the winter.
Timber Studs: While timber is a better insulator than steel, it still conducts heat much faster than the insulation tucked beside it.
Concrete Slabs: In many homes, the edge of the concrete slab is exposed to the outside air. Heat can travel through the floorboards, into the slab, and right out into the garden.
Windows and Doors: Metal window frames (like standard aluminium) are notorious for thermal bridging unless they are specifically designed with a “thermal break” in the middle.
How Can You Prevent Thermal Bridging?
The most effective way to prevent thermal bridging is to install a “thermal break,” which is a layer of low-conductivity material placed between the conductive frame and the external cladding. This essentially “breaks” the bridge, forcing the heat to slow down and stay where it belongs.
In Australia, the National Construction Code (NCC) actually requires thermal breaks for certain types of construction, especially steel framing. Here are the most common solutions:
1. Continuous Insulation
Instead of just putting insulation between the studs, you apply a continuous layer of insulation over the studs. This creates a seamless blanket around the house, ensuring there are no gaps for heat to exploit.
2. Using Thermal Break Tapes
For steel-framed sheds or homes, a simple but effective solution is applying high-density foam tape directly to the metal flange before the cladding is attached. This stops the direct transfer of heat from the cladding into the frame.
3. Reflective Foil Membranes
Specialised foil-faced products can reflect radiant heat while also providing a physical barrier that acts as a thermal break. These are particularly popular in Australia because they help tackle our intense summer sun.
Recommended Products to Combat Thermal Bridging
Choosing the right materials is crucial for a high-performing home. If you are looking to build or renovate, these products are specifically designed to stop heat transfer and improve your “R-value” (the measure of thermal resistance).
Kingspan Aircell Insulbreak 70 Insulation Roll
Kingspan Aircell Insulbreak 70 Insulation Roll
This is a 3-in-1 solution that provides an insulation layer, a radiant barrier, and a thermal break. It is specifically designed for steel-framed construction to meet Australian building standards.
RHINO Thermal Break Tape
A fast and cost-effective way to add a thermal break to steel studs. This high-density foam tape is essential for preventing “wicking” of heat through metal frames.
Kingspan Aircell Permishield 70 Insulation
Kingspan Aircell Permishield 70 Insulation
Ideal for behind-cladding applications, this product allows the building to “breathe” while providing excellent thermal resistance and breaking the thermal bridge.
Bradford Polyair Performa HD
A heavy-duty reflective insulation that is great for sheds and residential roofs, providing a significant barrier against heat flow.
Rhino Foam 80 Anti Glare
This product provides a great thermal barrier while being easy to install in the Australian sun thanks to its anti-glare coating, ensuring the installer isn’t blinded by reflections during the build.
The Long-Term Benefits of Fixing the Bridge
Beyond the comfort, you are protecting the “bones” of your home. By reducing the chance of condensation, you are preventing rot in timber frames and corrosion in steel frames. It is a one-time investment during the construction or renovation phase that pays for itself every single month when the electricity bill arrives.
If you are living in an older home and can’t easily tear down walls to add a thermal break, you can still help by focusing on your windows. Using heavy, floor-to-ceiling curtains or honeycomb blinds can create a “buffer” over the glass and frames, which are the most common thermal bridges in older Australian houses.
Ready to Optimise Your Home?
Thermal bridging might be invisible, but you can certainly feel its effects on your comfort and your wallet. Whether you are a DIYer or a professional builder, getting your insulation strategy right is the key to a high-performance home.
At Building Supplies Australia Network, we provide the highest quality construction materials to help you build smarter. We deliver directly to sites and homes across all major cities, including Adelaide, Brisbane, Melbourne, and Sydney. Order online today or request a quote for your next project.